
const int LED_Pin = 3;
void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  pinMode(LED_Pin, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:

  for (int i = 0; i < 256; i++) {
    analogWrite(LED_Pin, i);
    delay(5);
  }
  analogWrite(LED_Pin, 255);
  for (int i = 255; i > -1; i--) {
    analogWrite(LED_Pin, i);
    delay(5);
  }
}
